Method for preventing and treating pulmonary fibrosis

ABSTRACT

The present invention relates to a method for preventing and treating pulmonary fibrosis, comprising administering an effective amount of plasminogen to a subject.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a national stage filing under 35 U.S.C. 371 of International Patent Application Ser. No. PCT/CN2017/089057, filed Jun. 19, 2017, which claims priority to International Patent Application Ser. No. PCT/CN2016/110174, filed Dec. 15, 2016. The entire contents of these applications are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a method for preventing and treating pulmonary fibrosis, comprising administering an effective amount of plasminogen to a subject.

BACKGROUND ART

Fibrosis is a pathological change characterized by the activation and proliferation of fibroblasts, and increased fibrous connective tissues and decreased parenchymal cells in tissues and organs. Continuous progress can lead to structural destruction and loss of function of tissues and organs. Fibrosis of vital organs seriously affects the quality of life of patients and even endangers life. Tissue fibrosis is the leading cause of disability and death in many diseases worldwide. According to the relevant statistics of the United States, about 45% of the deaths due to various diseases in this country can be attributed to the diseases of tissue fibroplasia.

Fibrotic diseases comprise diseases affecting multiple systems, such as systemic sclerosis, multifocal fibrosis, scleroderma, and nephrogenic multisystem fibrosis, and further comprise organ- and tissue-specific diseases, such as skin, cardiac, pulmonary, hepatic, renal fibrosis, etc. Different fibrosis diseases have different etiologies, such as tissue and organ injury, infection, immune response and chronic inflammation; however, their common characteristics are excessive deposition of extracellular matrix (ECM) in tissues as well as organ and tissue remodeling^([1-3]).

Cardiac fibrosis occurs in the development and progression of a variety of heart diseases, such as viral myocarditis, myocardial infarction, and hypertensive heart disease. Excessive cardiac fibrosis leads to impaired cardiac function and is the main cause of heart failure in many diseases, wherein inhibition and reversal of myocardial fibrosis have become important links in the treatment of cardiovascular diseases.

Hepatic fibrosis refers to a pathological process of abnormal hyperplasia of connective tissue in the liver caused by various pathogenic factors, and excessive deposition of diffuse extracellular matrix in the liver. Hepatic fibrosis can be caused by a variety of factors, such as viral infection, inflammatory response, oxidative stress, and alcoholism. The pathological features of hepatic fibrosis are that there are large amounts of fibrous tissue hyperplasia and deposition in the portal area and hepatic lobule, but no interlobular septum has been formed. In hepatic cirrhosis, pseudolobules are formed, septa appear in the central venous area and the portal area, and the normal structure of the liver is destroyed. Further progression of hepatic fibrosis is called hepatic cirrhosis. Viral hepatitis is the main chronic liver disease in China. Hepatic tissue fibrosis in chronic viral hepatitis is associated with inflammation, necrosis, viral replication and the like in the liver, and is reversible at an early stage. Therefore, therapies such as antiviral therapy, body immune function adjustment, and protecting hepatocytes are combined with anti-fibrosis, which is an active measure to prevent hepatic fibrosis.

Pulmonary fibrosis diseases comprise idiopathic pulmonary fibrosis, sarcoidosis, allergic pneumonia, pneumoconiosis, drug-induced and radiation-induced fibrosis, and a broad spectrum of diseases with varying etiologies such as fibrogenic alveolitis associated with collagen vascular disease. The main pathological features comprise lung tissue mesenchymal cell proliferation, extracellular matrix proliferation and deposition, and remodeling of lung parenchyma. At present, anti-inflammation, anti-oxidation, anti-fibroblast proliferation, collagen deposition, lung transplantation and other measures are mainly used to treat pulmonary fibrosis.

Renal fibrosis is a pathological process in which extracellular matrix and inappropriate connective tissue accumulate in the kidney, leading to renal structural changes and impaired functions. It is also a common pathway for almost all renal diseases to progress to end-stage renal failure. The process of renal fibrosis involves inflammatory response, apoptosis of innate cells and immune cells, imbalance of a variety of regulatory factors of fibrosis, and the like; therefore, renal fibrosis can be resisted through anti-inflammation, anti-apoptosis, treatment against fibrosis factors and other ways.

Chronic lesions of tissues and organs are generally accompanied by fibrosis, for example, chronic inflammation and chronic lesions of the lung are accompanied by pulmonary fibrosis. Likewise, for hepatic fibrosis, for instance, hepatitis B, hepatitis C, alcoholic liver, fatty liver, schistosomiasis and the like are accompanied by early-stage hepatic fibrosis. Since the compensatory function of the liver is very strong, fibrotic lesions have been latent in a variety of chronic liver diseases and are generally discovered when they develop into hepatic cirrhosis. In fact, hepatic cirrhosis is a serious stage of hepatic fibrosis. Furthermore, for instance, chronic nephritis, glomerulitis, tubulitis and the like are all accompanied by renal fibrosis; and cardiovascular, cerebrovascular, and lower extremity vascular sclerosis, narrowing, or obstruction are all accompanied by vascular fibrosis.

Skin fibrosis forms scar tissues. Scar tissues are fibrous connective tissues in the aging stage formed by the remodeling and maturation of granulation tissues. In the case of trauma, fibroblasts divide and proliferate, migrate to the damaged site, produce extracellular matrix, form scar tissue, and repair trauma.

The formation of scars is a process of progressive fibrosis of granulation tissues. As such, there are more and more reticular fibers and collagen fibers, and the reticular fibers become collagenized and the collagen fibers become thicker; meanwhile, fewer and fewer fibroblasts are left, and a small number of the remaining ones are transformed into fibrocytes; the interstitial fluid is gradually absorbed, and neutrophils, macrophages, lymphocytes and plasma cells disappear successively; and capillaries are closed, degenerated, and disappear, leaving few arterioles and venules. In this way, the granulation tissue is transformed into a scar tissue composed mainly of collagen fibers with few blood vessels, which is white and tough under the naked eyes.

Scar tenacity and inelasticity, together with scar contraction can cause organ deformation and dysfunction. Therefore, scarring around the joints and vital organs often causes joint spasm or restricted movement, for instance, lumen stenosis may be caused in the lumen organs such as the digestive tract and the urinary tract, and movement disorder may be caused near the joints. Cicatricial adhesions between organs or between organs and body cavity walls often affect their function to varying degrees. If extensive fibrosis and hyaline degeneration occur after extensive injury in the organ, organ sclerosis will occur.

Systemic sclerosis (SSc), also known as scleroderma, is a systemic autoimmune disease characterized by localized or diffuse skin thickening and fibrosis. The lesions are characterized by fibrous hyperplasia of skin and onion skin changes of blood vessels, which eventually lead to skin sclerosis and vascular ischemia. The disease is clinically characterized by localized or diffuse skin thickening and fibrosis. In addition to skin involvement, it can also affect the internal organs (heart, lungs, digestive tract and other organs).

Atherosclerosis generally leads to ischemic injuries of tissues and organs, which in turn causes fibrotic lesions in tissues and organs. Atherosclerosis is a chronic, progressive arterial disease in which the fat deposited in the arteries partially or completely blocks blood flow. Atherosclerosis occurs when the otherwise smooth and solid arterial intima becomes roughened and thickened and is blocked by fat, fibrin, calcium, and cellular debris. Atherosclerosis is the chronic inflammatory hyperplasia of arterial intima, which leads to the stenosis or occlusion of large- and medium-sized arterial lumens, and causes ischemic injuries, fibrosis and even necrosis of corresponding organs and tissues.

Atherosclerosis is closely related to diabetes mellitus, which is manifested by early onset, severe degree and poor prognosis of atherosclerosis in diabetic patients, and atherosclerosis is the main cause of death in diabetic patients. Clinically, it has been found that the pathological changes of coronary arteries in diabetic patients are substantially characterized by more affected vessels, severe coronary artery stenosis, and more diffuse and severe lesions, and that the mechanism is mostly attributed to abnormal glucose metabolism causing atherosclerosis. With further in-depth research, more results indicate that diabetes mellitus-induced atherosclerosis is not caused by a single factor, but through a variety of pathways and more complex mechanisms to induce and promote the development and progression of atherosclerosis, such as polarization of macrophages, macrophage migration inhibitory factor pathway, advanced glycation end products pathway, scavenger receptor upregulation, insulin resistance, ubiquitin proteasome system activation, and platelet-derived growth factor activation pathway.^([4])

At present, a large number of people are suffering from fibrosis diseases caused by various reasons, patients often have multiple organs and tissues affected, such diseases still lack effective therapies, and the social and economic burdens are relatively heavy. The studies of the present invention found that plasminogen can ameliorate tissue and organ fibrosis, and improve tissue and organ functions, thus opening up a new field for preventing and treating tissue and organ fibrosis and its related conditions.

SUMMARY OF THE INVENTION

The present invention relates to the following items:

1. A method for preventing or treating pulmonary collagen deposition or fibrosis caused by a pulmonary tissue injury in a subject, comprising administering an effective amount of plasminogen to the subject.

2. The method of item 1, wherein the injury comprises an ischemic reperfusion injury, an immune injury, a chemical-induced injury, an inflammatory injury, and a cancer-induced injury.

3. The method of item 2, wherein the injury comprises an autoimmune response-induced injury.

4. A method for preventing or treating pulmonary collagen deposition or fibrosis in a subject, comprising administering an effective amount of plasminogen to the subject, wherein the subject is susceptible to pulmonary fibrosis, has a tendency of pulmonary fibrosis, or suffers from other diseases accompanied by pulmonary fibrosis.

5. A method for treating pulmonary fibrosis in a subject with idiopathic pulmonary fibrosis, comprising administering an effective amount of plasminogen to the subject.

6. A method for preventing or treating pulmonary collagen deposition or fibrosis caused or complicated by atherosclerosis in a subject, comprising administering an effective amount of plasminogen to the subject.

7. A method for preventing or treating pulmonary collagen deposition or fibrosis caused or complicated by hyperlipemia in a subject, comprising administering an effective amount of plasminogen to the subject.

8. The method of item 7, wherein the hyperlipemia comprises one or more selected from: an elevated blood triglyceride level, an elevated total blood cholesterol level, increased blood low-density lipoprotein, and increased blood very low-density lipoprotein.

9. A method for preventing or treating pulmonary collagen deposition or fibrosis caused by inhalation of toxic chemicals, radiation, or environmental pollutants in a subject, comprising administering an effective amount of plasminogen to the subject.

10. The method of item 9, wherein the environmental pollutants comprise fog and haze.

11. The method of item 9, wherein the environmental pollutants comprise dust from a workshop or a workplace.

12. The method of item 9, wherein the environmental pollutants comprise inhalable PM2.5 particles.

13. A method for preventing or treating pulmonary collagen deposition or fibrosis caused or accompanied by bacterial, viral, chlamydial, spirochetal, or rickettsial infection in the lung tissue of a subject, comprising administering an effective amount of plasminogen to the subject.

14. The method of item 13, wherein the bacterial infection is Mycobacterium tuberculosis infection.

15. A method for preventing or treating pulmonary collagen deposition or fibrosis caused or accompanied by a pulmonary lesion in a subject, comprising administering an effective amount of plasminogen to the subject.

16. The method of item 15, wherein the pulmonary lesion is pneumonia, lung cancer, pulmonary embolism, pulmonary tuberculosis, pulmonary heart disease, and pulmonary injury.

17. A method for preventing or treating pulmonary fibrosis accompanied by chronic obstructive pulmonary disease in a subject, comprising administering an effective amount of plasminogen to the subject.

18. A method for preventing or treating a pulmonary fibrosis-related condition in a subject, comprising administering an effective amount of plasminogen to the subject.

19. The method of item 18, wherein the pulmonary fibrosis-related condition comprises a condition resulting from decreased pulmonary function, pulmonary dysfunction or loss of pulmonary function due to pulmonary fibrosis.

20. The method of item 19, wherein the pulmonary fibrosis-related condition comprises pulmonary arterial hypertension, pulmonary heart disease, dyspnea, and pulmonary encephalopathy.

21. The method of any one of items 1 to 20, wherein the plasminogen is administered in combination with one or more other drugs or therapeutic means.

22. The method of item 21, wherein the other drugs comprise: a hypolipidemic drug, an anti-platelet drug, an antihypertensive drug, a vasodilator, a hypoglycemic drug, an anticoagulant drug, a thrombolytic drug, a hepatoprotective drug, an anti-fibrosis drug, an anti-arrhythmia drug, a cardiotonic drug, a diuretic drug, an anti-tumor drug, a radiotherapeutic or chemotherapeutic drug, an inflammatory regulatory drug, an immunomodulatory drug, an antiviral drug, and an antibiotic.

23. The method of any one of items 1 to 22, wherein the plasminogen has at least 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID No. 2, 6, 8, 10 or 12, and still has the plasminogen activity.

24. The method of any one of items 1 to 23, wherein the plasminogen is a protein that has 1-100, 1-90, 1-80, 1-70, 1-60, 1-50, 1-45, 1-40, 1-35, 1-30, 1-25, 1-20, 1-15, 1-10, 1-5, 1-4, 1-3, 1-2 or 1 amino acid added, deleted and/or substituted in SEQ ID No. 2, 6, 8, 10 or 12, and still has the plasminogen activity.

25. The method of any one of items 1 to 24, wherein the plasminogen is a protein that comprises a plasminogen active fragment and still has the plasminogen activity.

26. The method of any one of items 1 to 25, wherein the plasminogen is selected from Glu-plasminogen, Lys-plasminogen, mini-plasminogen, micro-plasminogen, delta-plasminogen or their variants that retain the plasminogen activity.

27. The method of any one of items 1 to 26, wherein the plasminogen is a natural or synthetic human plasminogen, or a variant or fragment thereof that still retains the plasminogen activity.

28. The method of any one of items 1 to 26, wherein the plasminogen is an ortholog of human plasminogen from a primate or a rodent, or a variant or fragment thereof that still retains the plasminogen activity.

29. The method of any one of items 1 to 28, wherein the amino acids of the plasminogen are as shown in SEQ ID No. 2, 6, 8, 10 or 12.

30. The method of any one of items 1 to 29, wherein the plasminogen is a natural human plasminogen.

31. The method of any one of items 1 to 30, wherein the subject is a human.

32. The method of any one of items 1 to 31, wherein the subject has a lack or deficiency of plasminogen.

33. The method of any one of items 1 to 32, wherein the lack or deficiency is congenital, secondary and/or local.

34. A plasminogen for use in the method of any one of items 1 to 33.

35. A pharmaceutical composition, comprising a pharmaceutically acceptable carrier and the plasminogen for use in the method of any one of items 1 to 33.

36. A preventive or therapeutic kit comprising: (i) the plasminogen for use in the method of any one of items 1 to 33, and (ii) a means for delivering the plasminogen to the subject.

37. The kit of item 36, wherein the means is a syringe or a vial.

38. The kit of item 36 or 37, further comprising a label or an instruction for use indicating the administration of the plasminogen to the subject to implement the method of any one of items 1 to 33.

39. An article of manufacture, comprising:

a container comprising a label; and

(i) the plasminogen for use in the method of any one of items 1 to 33 or a pharmaceutical composition comprising the plasminogen, wherein the label indicates the administration of the plasminogen or the composition to the subject to implement the method of any one of items 1 to 33.

40. The kit of any one of items 36 to 38 or the article of manufacture of item 39, further comprising one or more additional means or containers containing other drugs.

41. The kit or the article of manufacture of item 40, wherein the other drugs are selected from the group of a hypolipidemic drug, an anti-platelet drug, an antihypertensive drug, a vasodilator, a hypoglycemic drug, an anticoagulant drug, a thrombolytic drug, a hepatoprotective drug, an anti-fibrosis drug, an anti-arrhythmia drug, a cardiotonic drug, a diuretic drug, an anti-tumor drug, a radiotherapeutic or chemotherapeutic drug, an inflammatory regulatory drug, an immunomodulatory drug, an antiviral drug, and an antibiotic.

In one aspect, the present invention relates to a method for preventing and/or treating collagen deposition or fibrosis of a tissue and an organ and its related conditions in a subject, comprising administering an effective amount of plasminogen to the subject, wherein the subject is susceptible to tissue and organ fibrosis, has a tendency of tissue and organ fibrosis, or suffers from other diseases accompanied by tissue and organ fibrosis. The present invention further relates to the use of plasminogen for preventing and/or treating collagen deposition or fibrosis of a tissue and an organ and its related conditions in a subject. The present invention further relates to the use of plasminogen in the preparation of a medicament for preventing and/or treating collagen deposition or fibrosis of a tissue and an organ and its related conditions in a subject. In addition, the present invention further relates to the plasminogen for preventing and/or treating collagen deposition or fibrosis of a tissue and an organ and its related conditions in a subject. In some embodiments, the collagen deposition or fibrosis of a tissue and an organ comprises skin fibrosis, vascular fibrosis, cardiac fibrosis, pulmonary fibrosis, hepatic fibrosis, and renal fibrosis. In some other embodiments, the collagen deposition or fibrosis of a tissue and an organ comprises collagen deposition or fibrosis of a tissue and an organ elicited or accompanied by injuries caused by infection, inflammation, hypersensitivity, tumors, tissue ischemia, tissue and organ congestion, chemicals, radiation or environmental pollution. Specifically, the collagen deposition or fibrosis of a tissue and an organ comprises collagen deposition or fibrosis of a tissue and an organ caused by a tissue and organ lesion due to a bacterial, viral or parasitic infection, wherein the collagen deposition or fibrosis of a tissue and an organ comprises pulmonary fibrosis caused by Mycobacterium tuberculosis infection, hepatic fibrosis caused by a hepatitis B virus, hepatitis C virus or hepatitis E virus infection, and hepatic fibrosis caused by schistosomiasis infection. In some embodiments, the collagen deposition or fibrosis of a tissue and an organ results from an aseptic inflammation or an autoimmune response. Specifically, the collagen deposition or fibrosis of a tissue and an organ is renal fibrosis caused by chronic glomerulonephritis, pyelonephritis, nephrotic syndrome, renal insufficiency, and uremia. In some other embodiments, the collagen deposition or fibrosis of a tissue and an organ results from a tissue and organ injury caused by cancer. Specifically, the collagen deposition or fibrosis of a tissue and an organ is pulmonary fibrosis caused by lung cancer, hepatic fibrosis caused by liver cancer, or renal fibrosis caused by kidney cancer. In some other embodiments, the collagen deposition or fibrosis of a tissue and an organ results from a chronic ischemic tissue injury. Specifically, the collagen deposition or fibrosis of a tissue and an organ is cardiac ischemic fibrosis caused by coronary atherosclerosis and coronary heart disease, and/or renal fibrosis caused by a chronic ischemic renal injury. In some other embodiments, the collagen deposition or fibrosis of a tissue and an organ results from tissue and organ congestion caused by a cardiovascular disease. Specifically, the collagen deposition or fibrosis of a tissue and an organ is hepatic congestion or pulmonary congestion. In some embodiments, the collagen deposition or fibrosis of a tissue and an organ results from a drug. Specifically, the collagen deposition or fibrosis of a tissue and an organ is drug-induced hepatic fibrosis or renal fibrosis. In some embodiments, the collagen deposition or fibrosis of a tissue and an organ is pulmonary fibrosis caused by inhaled chemicals or environmental pollutants. In the above-mentioned embodiments, the collagen deposition or fibrosis of a tissue and an organ results from a systemic immune disease such as systemic lupus erythematosus, systemic sclerosis, and ankylosing spondylitis. In some embodiments, the tissue and organ fibrosis is idiopathic pulmonary fibrosis.

In the above-mentioned embodiments, the tissue and organ fibrosis-related condition comprises a condition resulting from function weakening, dysfunction or loss of function of a tissue or an organ due to a fibrotic lesion. Specifically, the tissue and organ fibrosis-related condition comprises atherosclerosis, coronary heart disease, angina pectoris, myocardial infarction, arrhythmia, cerebral ischemia, cerebral infarction, renal insufficiency, uremia, hepatic dysfunction, hepatic cirrhosis, hepatic coma, dyspnea, emphysema, pulmonary heart disease, pulmonary fibrosis, and ankylosing spondylitis.

In the above-mentioned embodiments, the plasminogen is administered in combination with one or more other drugs or therapies. Specifically, the plasminogen is administered in combination with one or more drugs selected from: a hypolipidemic drug, an anti-platelet drug, an antihypertensive drug, a vasodilator, a hypoglycemic drug, an anticoagulant drug, a thrombolytic drug, a hepatoprotective drug, an anti-fibrosis drug, an anti-arrhythmia drug, a cardiotonic drug, a diuretic drug, an anti-tumor drug, a radiotherapeutic or chemotherapeutic drug, an inflammatory regulatory drug, an immunomodulatory drug, an antiviral drug, and an antibiotic.

In the above-mentioned embodiments, the plasminogen has at least 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID No. 2, 6, 8, 10 or 12, and still has the activity of plasminogen.

In the above-mentioned embodiments, the amino acids of the plasminogen are as shown in SEQ ID No. 2, 6, 8, 10 or 12. In some embodiments, the plasminogen is a protein that has 1-100, 1-90, 1-80, 1-70, 1-60, 1-50, 1-45, 1-40, 1-35, 1-30, 1-25, 1-20, 1-15, 1-10, 1-5, 1-4, 1-3, 1-2 or 1 amino acid added, deleted and/or substituted in SEQ ID No. 2, 6, 8, 10 or 12, and still has the activity of plasminogen.

In the above-mentioned embodiments, the plasminogen is a protein that comprises a plasminogen active fragment and still has the activity of plasminogen. Specifically, the plasminogen is selected from Glu-plasminogen, Lys-plasminogen, mini-plasminogen, micro-plasminogen, delta-plasminogen or their variants that retain the plasminogen activity.

In the above-mentioned embodiments, the plasminogen is a natural or synthetic human plasminogen, or a variant or fragment thereof that still retains the plasminogen activity. In some embodiments, the plasminogen is an ortholog of human plasminogen from a primate or a rodent, or a variant or fragment thereof that still retains the plasminogen activity. For example, the plasminogen is an ortholog of plasminogen from primates or rodents, for example, an ortholog of plasminogen from gorillas, rhesus monkeys, murine, cows, horses and dogs. Most preferably, the amino acid sequence of the plasminogen of the present invention is as shown in SEQ ID No. 2, 6, 8, 10 or 12.

In the above-mentioned embodiments, the subject is a human. In some embodiments, the subject has a lack or deficiency of plasminogen. Specifically, the lack or deficiency is congenital, secondary and/or local.

In one embodiment, the plasminogen is administered by systemic or topical route, preferably by the following routes: topical, intravenous, intramuscular, subcutaneous, inhalation, intraspinal, local injection, intraarticular injection or rectal route. In one embodiment, the topical administration is performed by direct administration to osteoporotic areas, for example through a means such as a dressing and a catheter.

In one embodiment, the plasminogen is administered in combination with a suitable polypeptide carrier or stabilizer. In one embodiment, the plasminogen is administered at a dosage of 0.0001-2000 mg/kg, 0.001-800 mg/kg, 0.01-600 mg/kg, 0.1-400 mg/kg, 1-200 mg/kg, 1-100 mg/kg or 10-100 mg/kg (by per kg of body weight) or 0.0001-2000 mg/cm², 0.001-800 mg/cm², 0.01-600 mg/cm², 0.1-400 mg/cm², 1-200 mg/cm², 1-100 mg/cm² or 10-100 mg/cm² (by per square centimeter of body surface area) daily, preferably the dosage is repeated at least once, preferably the dosage is administered at least daily. In the case of local administration, the above dosages may also be further adjusted depending on the circumstances. In one aspect, the present invention relates to a pharmaceutical composition, comprising a pharmaceutically acceptable carrier and the plasminogen for use in the method of the present invention.

In another aspect, the present invention relates to a preventive or therapeutic kit comprising: (i) the plasminogen for use in the method of the present invention, and (ii) a means for delivering the plasminogen to the subject, in particular, the means is a syringe or a vial. In some embodiments, the kit further comprises a label or an instruction for use indicating the administration of the plasminogen to the subject to implement the methods of the present invention.

In another aspect, the present invention further relates to an article of manufacture comprising: a container comprising a label; and (i) the plasminogen for use in the methods of the present invention or a pharmaceutical composition comprising the plasminogen, wherein the label indicates the administration of the plasminogen or the composition to the subject to implement the methods of the present invention.

In the above-mentioned embodiments, the kit or the article of manufacture further comprises one or more additional means or containers containing other drugs. In some embodiments, the other drugs are selected from the group of: a hypolipidemic drug, an anti-platelet drug, an antihypertensive drug, a vasodilator, a hypoglycemic drug, an anticoagulant drug, a thrombolytic drug, a hepatoprotective drug, an anti-fibrosis drug, an anti-arrhythmia drug, a cardiotonic drug, a diuretic drug, an anti-tumor drug, a radiotherapeutic or chemotherapeutic drug, an inflammatory regulatory drug, an immunomodulatory drug, an antiviral drug, and an antibiotic.

Definition

“Fibrosis” is a lesion characterized by the activation and proliferation of fibroblasts, and increased fibrous connective tissue and decreased parenchymal cells in tissues and organs, and structural destruction and loss of function of tissues and organs, after the tissues and organs such as lung, liver, kidney, blood vessel, peritoneum, pancreas and skin are continuously injured due to various causes such as inflammation, infection, immune response, ischemia, chemicals and radiation. The term can be used interchangeably with “fibrotic lesion”. The term “fibrotic lesion” encompasses fibrotic lesions in tissues and organs, such as cardiac fibrosis, pulmonary fibrosis, hepatic fibrosis, renal fibrosis, vascular fibrosis and skin fibrosis, which are caused by various factors, and further comprises the fibrotic lesions in tissues and organs, such as cardiac fibrosis, pulmonary fibrosis, hepatic fibrosis, renal fibrosis, vascular fibrosis and skin fibrosis, which are associated with the development and progression of various diseases.

After the development of fibrotic lesions in tissues and organs, their normal structures change, and the corresponding functions are weakened or lost, and thus the resulting related conditions are called “tissue and organ fibrosis-related conditions”.

“Cardiac fibrosis” refers to the fibrotic lesion occurring in the development and progression of the cardiac tissue injury caused or accompanied by various factors (such as inflammation, infection, immune response, ischemia, chemicals, and radiation), or of heart diseases caused by various factors. Cardiac fibrosis lesions lead to impaired cardiac function, and thus the resulting related conditions are called “cardiac fibrosis-related conditions”, including but not limited to the symptoms and conditions of organ and tissue ischemia caused by impaired cardiac function, such as coronary heart disease, angina pectoris, myocardial infarction, arrhythmia, cerebral ischemia, dyspnea, and renal insufficiency.

“Hepatic fibrosis” refers to pathological changes (lesions) caused or accompanied by various factors (such as inflammation, infection (such as viral infection), immune response, ischemia, chemicals, radiation, oxidative stress, and alcoholism), comprising the abnormal hyperplasia of connective tissue in the liver, excessive deposition of diffuse extracellular matrix in the liver, and destruction of the normal structure of liver. Further progression of hepatic fibrosis is hepatic cirrhosis, and is also encompassed within the scope of the term “hepatic fibrosis” of the present invention. Hepatic fibrosis lesions lead to impaired hepatic function, and thus the resulting related conditions are called “hepatic fibrosis-related conditions”.

“Pulmonary fibrosis” refers to a pathological process caused by lung tissue mesenchymal cell proliferation, extracellular matrix proliferation and deposition, and lung parenchymal remodeling which are caused or accompanied by various factors (such as inflammation, infection, immune response, ischemia, chemicals, and radiation). Pulmonary fibrosis lesions lead to impaired pulmonary function, and thus the resulting related conditions are called “pulmonary fibrosis-related conditions”.

“Renal fibrosis” refers to a pathological process in which abnormal accumulation of connective tissues in the kidney caused or accompanied by various factors (such as inflammation, infection, immune response, ischemia, chemicals, and radiation) occurs, leading to renal structural changes and impaired functions. The renal fibrosis lesion is a common pathway by which almost all renal diseases progress to the later stages.

Renal fibrosis lesions lead to impaired renal function, and thus the resulting related conditions are called “renal fibrosis-related conditions”, for instance, renal insufficiency, renal failure, uremia, etc.

Chronic lesions of tissues and organs are generally accompanied by fibrosis, for example, chronic inflammation and chronic lesions of the lung are accompanied by pulmonary fibrosis. Likewise, for hepatic fibrosis, for example, hepatitis B, hepatitis C, alcoholic liver, fatty liver, schistosomiasis and the like are accompanied by early-stage hepatic fibrosis. Furthermore, for instance, chronic nephritis, glomerulitis, tubulitis and the like are all accompanied by renal fibrosis; and cardiovascular, cerebrovascular, and lower extremity vascular sclerosis, narrowing, or obstruction are all accompanied by vascular fibrosis. In the present invention, the term “fibrosis” or “fibrotic lesion” encompasses fibrotic lesions generally accompanied by chronic lesions of various tissues and organs of the body.

“Systemic sclerosis”, also known as “scleroderma”, is a systemic autoimmune disease characterized by localized or diffuse skin thickening and fibrosis. The lesions are characterized by fibrous hyperplasia of skin and onion skin changes of blood vessels, which eventually lead to skin sclerosis and vascular ischemia. The disease is clinically characterized by localized or diffuse skin thickening and fibrosis. In addition to skin involvement, it can also affect the internal organs (heart, lungs, digestive tract and other organs).

“Atherosclerosis” is a chronic, progressive arterial disease in which the fat deposited in the arteries partially or completely blocks blood flow. Atherosclerosis is a progressive process. When the concentration of lipids in the blood is greatly increased, fatty streaks form along the arterial wall. These streaks can lead to deposits of fat and cholesterol, which attach to the otherwise smooth arterial intima and thus form nodules. Underneath these nodules, fibrotic scar tissue develops, leading to calcium deposition. The calcium deposits gradually develop into a chalky hard film (referred to as atherosclerotic plaque) that cannot be removed. When an artery connected to a tissue or an organ in the body is blocked, the ischemic injury to the tissue or organ caused by the blocked artery in the tissue or organ may lead to a fibrotic lesion of the tissue or organ, such as fibrosis of the heart, lung, liver, kidney, blood vessel, peritoneum, pancreas and skin.

Diabetes mellitus generally occurs with the development of atherosclerosis, and the mechanism is mostly attributed to atherosclerosis caused by abnormal glucose metabolism. With further in-depth research, more results indicate that diabetes mellitus-induced atherosclerosis is not caused by a single factor, but through a variety of ways and a more complex mechanism to induce and promote the development and progression of atherosclerosis^([4]). Diabetes mellitus and its concomitant atherosclerosis may lead to tissue and organ injuries and fibrosis, such as fibrosis of the heart, lung, liver, kidney, blood vessel, peritoneum, pancreas, skin, and other tissues and organs.

DETAILED DESCRIPTION OF EMBODIMENTS

Plasmin is a key component of the plasminogen activation system (PA system). It is a broad-spectrum protease that can hydrolyze several components of the extracellular matrix (ECM), including fibrin, gelatin, fibronectin, laminin, and proteoglycan^([5]). In addition, plasmin can activate some pro-matrix metalloproteinases (pro-MMPs) to form active matrix metalloproteinases (MMPs). Therefore, plasmin is considered to be an important upstream regulator of extracellular proteolysis^([6,7]). Plasmin is formed by the proteolysis of plasminogen by two physiological PAs: tissue plasminogen activator (tPA) or urokinase-type plasminogen activator (uPA). Due to the relatively high level of plasminogen in plasma and other body fluids, it is traditionally believed that the regulation of the PA system is primarily achieved through the levels of PA synthesis and activity. The synthesis of PA system components is strictly regulated by different factors, such as hormones, growth factors and cytokines. In addition, there are also specific physiological inhibitors of plasmin and PAs. The main inhibitor of plasmin is α2-antiplasmin. The activity of PAs is simultaneously inhibited by the plasminogen activator inhibitor-1 (PAI-1) of uPA and tPA and regulated by the plasminogen activator inhibitor-2 (PAI-2) that primarily inhibits uPA. There are uPA-specific cell surface receptors (uPARs) that have direct hydrolytic activity on certain cell surfaces^([8,9]).

Plasminogen is a single-stranded glycoprotein composed of 791 amino acids and has a molecular weight of about 92 kDa^([10,11].) Plasminogen is mainly synthesized in the liver and is abundantly present in the extracellular fluid. The content of plasminogen in plasma is about 2 μM. Therefore, plasminogen is a huge potential source of proteolytic activity in tissues and body fluids^([12,13]). Plasminogen exists in two molecular forms: glutamic acid-plasminogen (Glu-plasminogen) and lysine-plasminogen (Lys-plasminogen). The naturally secreted and uncleaved forms of plasminogen have an amino-terminal (N-terminal) glutamic acid and are therefore referred to as glutamic acid-plasminogen. However, in the presence of plasmin, glutamic acid-plasminogen is hydrolyzed to lysine-plasminogen at Lys76-Lys77. Compared with glutamic acid-plasminogen, lysine-plasminogen has a higher affinity for fibrin and can be activated by PAs at a higher rate. The Arg560-Val561 peptide bond between these two forms of plasminogen can be cleaved by uPA or tPA, resulting in the formation of plasmin as a disulfide-linked double-strand protease^([14]). The amino-terminal portion of plasminogen contains five homotrimeric rings, i.e., the so-called kringles, and the carboxy-terminal portion contains a protease domain. Some kringles contain lysine-binding sites that mediate the specific interaction of plasminogen with fibrin and its inhibitor α2-AP. A newly discovered plasminogen is a 38 kDa fragment, comprising kringles 1-4, is a potent inhibitor of angiogenesis. This fragment is named as angiostatin and can be produced by proteolysis of plasminogen by several proteases.

The main substrate of plasmin is fibrin, and the dissolution of fibrin is the key to prevent pathological thrombosis^([15]). Plasmin also has substrate specificity for several components of ECM, including laminin, fibronectin, proteoglycan and gelatin, indicating that plasmin also plays an important role in ECM remodeling^([11,16,17]). Indirectly, plasmin can also degrade other components of ECM by converting certain protease precursors into active proteases, including MMP-1, MMP-2, MMP-3 and MMP-9. Therefore, it has been proposed that plasmin may be an important upstream regulator of extracellular proteolysis^([18]). In addition, plasmin has the ability to activate certain potential forms of growth factors^([19-21]). In vitro, plasmin can also hydrolyze components of the complement system and release chemotactic complement fragments.

“Plasmin” is a very important enzyme that exists in the blood and can hydrolyze fibrin clots into fibrin degradation products and D-dimers.

“Plasminogen” is the zymogenic form of plasmin, and based on the sequence in the swiss prot and calculated from the amino acid sequence (SEQ ID No. 4) of the natural human plasminogen containing a signal peptide, is a glycoprotein composed of 810 amino acids, which has a molecular weight of about 90 kD and is synthesized mainly in the liver and capable of circulating in the blood; and the cDNA sequence encoding this amino acid sequence is as shown in SEQ ID No. 3. Full-length plasminogen contains seven domains: a C-terminal serine protease domain, an N-terminal Pan Apple (PAp) domain and five Kringle domains (Kringles 1-5). Referring to the sequence in the swiss prot, the signal peptide comprises residues Met1-Gly19, PAp comprises residues Glu20-Val98, Kringle 1 comprises residues Cys103-Cys181, Kringle 2 comprises residues Glu184-Cys262, Kringle 3 comprises residues Cys275-Cys352, Kringle 4 comprises residues Cys377-Cys454, and Kringle 5 comprises residues Cys481-Cys560. According to the NCBI data, the serine protease domain comprises residues Val581-Arg804.

Glu-plasminogen is a natural full-length plasminogen and is composed of 791 amino acids (without a signal peptide of 19 amino acids); the cDNA sequence encoding this sequence is as shown in SEQ ID No. 1; and the amino acid sequence is as shown in SEQ ID No. 2. In vivo, Lys-plasminogen, which is formed by hydrolysis of amino acids at positions 76-77 of Glu-plasminogen, is also present, as shown in SEQ ID No. 6; and the cDNA sequence encoding this amino acid sequence is as shown in SEQ ID No. 5. δ-plasminogen is a fragment of full-length plasminogen that lacks the structure of Kringle 2-Kringle 5 and contains only Kringle 1 and the serine protease domain^([22,23].) The amino acid sequence (SEQ ID No. 8) of δ-plasminogen has been reported in the literature^([23]), and the cDNA sequence encoding this amino acid sequence is as shown in SEQ ID No. 7. Mini-plasminogen is composed of Kringle 5 and the serine protease domain, and has been reported in the literature to comprise residues Val443-Asn791 (with the Glu residue of the Glu-plasminogen sequence that does not contain a signal peptide as the starting amino acid)^([24]); the amino acid sequence is as shown in SEQ ID No. 10; and the cDNA sequence encoding this amino acid sequence is as shown in SEQ ID No. 9. Micro-plasminogen comprises only the serine protease domain, the amino acid sequence of which has been reported in the literature to comprise residues Ala543-Asn791 (with the Glu residue of the Glu-plasminogen sequence that does not contain a signal peptide as the starting amino acid)^([25]), and the sequence of which has been also reported in patent document CN 102154253 A to comprise residues Lys531-Asn791 (with the Glu residue of the Glu-plasminogen sequence that does not contain a signal peptide as the starting amino acid) (the sequence in this patent application refers to the patent document CN 102154253 A); the amino acid sequence is as shown in SEQ ID No. 12; and the cDNA sequence encoding this amino acid sequence is as shown in SEQ ID No. 11.

In the present invention, “plasmin” is used interchangeably with “fibrinolysin” and “fibrinoclase”, and the terms have the same meaning; and “plasminogen” is used interchangeably with “profibrinolysin” and “fibrinoclase zymogen”, and the terms have the same meaning.

In the present application, the meaning of “lack” in plasminogen is that the content or activity of plasminogen in the body of a subject is lower than that of a normal person, which is low enough to affect the normal physiological function of the subject; and the meaning of “deficiency” in plasminogen is that the content or activity of plasminogen in the body of a subject is significantly lower than that of a normal person, or even the activity or expression is extremely small, and only through exogenous supply can the normal physiological function be maintained.

Those skilled in the art can understand that all the technical solutions of the plasminogen of the present invention are suitable for plasmin. Therefore, the technical solutions described in the present invention cover plasminogen and plasmin.

In the course of circulation, plasminogen is in a closed, inactive conformation, but when bound to thrombi or cell surfaces, it is converted into an active plasmin in an open conformation under the mediation of a plasminogen activator (PA). The active plasmin can further hydrolyze the fibrin clots to fibrin degradation products and D-dimers, thereby dissolving the thrombi. The PAp domain of plasminogen comprises an important determinant that maintains plasminogen in an inactive, closed conformation, and the KR domain is capable of binding to lysine residues present on receptors and substrates. A variety of enzymes that can serve as plasminogen activators are known, including: tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), kallikrein, coagulation factor XII (Hagmann factor), and the like.

“Plasminogen active fragment” refers to an active fragment in the plasminogen protein that is capable of binding to a target sequence in a substrate and exerting the proteolytic function. The technical solutions of the present invention involving plasminogen encompass technical solutions in which plasminogen is replaced with a plasminogen active fragment. The plasminogen active fragment of the present invention is a protein comprising a serine protease domain of plasminogen. Preferably, the plasminogen active fragment of the present invention comprises SEQ ID No. 14, or an amino acid sequence having an amino acid sequence identity of at least 80%, 90%, 95%, 96%, 97%, 98% or 99% with SEQ ID No. 14. Therefore, plasminogen of the present invention comprises a protein containing the plasminogen active fragment and still having the plasminogen activity.

At present, methods for determining plasminogen and its activity in blood include: detection of tissue plasminogen activator activity (t-PAA), detection of tissue plasminogen activator antigen (t-PAAg) in plasma, detection of tissue plasminogen activity (plgA) in plasma, detection of tissue plasminogen antigen (plgAg) in plasma, detection of activity of the inhibitor of tissue plasminogen activators in plasma, detection of inhibitor antigens of tissue plasminogen activators in plasma and detection of plasmin-anti-plasmin (PAP) complex in plasma. The most commonly used detection method is the chromogenic substrate method: streptokinase (SK) and a chromogenic substrate are added to a test plasma, the PLG in the test plasma is converted into PLM by the action of SK, PLM acts on the chromogenic substrate, and then it is determined that the increase in absorbance is directly proportional to plasminogen activity using a spectrophotometer. In addition, plasminogen activity in blood can also be determined by immunochemistry, gel electrophoresis, immunonephelometry, radioimmuno-diffusion and the like.

“Orthologues or orthologs” refer to homologs between different species, including both protein homologs and DNA homologs, and are also known as orthologous homologs and vertical homologs. The term specifically refers to proteins or genes that have evolved from the same ancestral gene in different species. The plasminogen of the present invention includes human natural plasminogen, and also includes orthologues or orthologs of plasminogens derived from different species and having plasminogen activity.

“Conservatively substituted variant” refers to one in which a given amino acid residue is changed without altering the overall conformation and function of the protein or enzyme, including, but not limited to, replacing an amino acid in the amino acid sequence of the parent protein by an amino acid with similar properties (such as acidity, alkalinity, hydrophobicity, etc.). Amino acids with similar properties are well known. For example, arginine, histidine and lysine are hydrophilic basic amino acids and are interchangeable. Similarly, isoleucine is a hydrophobic amino acid that can be replaced by leucine, methionine or valine. Therefore, the similarity of two proteins or amino acid sequences with similar functions may be different. For example, the similarity (identity) is 70%-99% based on the MEGALIGN algorithm. “Conservatively substituted variant” also includes a polypeptide or enzyme having amino acid identity of 60% or more, preferably 75% or more, more preferably 85% or more, even more preferably 90% or more as determined by the BLAST or FASTA algorithm, and having the same or substantially similar properties or functions as the natural or parent protein or enzyme.

“Isolated” plasminogen refers to the plasminogen protein that is isolated and/or recovered from its natural environment. In some embodiments, the plasminogen will be purified (1) to a purity of greater than 90%, greater than 95% or greater than 98% (by weight), as determined by the Lowry method, such as more than 99% (by weight); (2) to a degree sufficiently to obtain at least 15 residues of the N-terminal or internal amino acid sequence using a spinning cup sequenator; or (3) to homogeneity, which is determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing or non-reducing conditions using Coomassie blue or silver staining. Isolated plasminogen also includes plasminogen prepared from recombinant cells by bioengineering techniques and separated by at least one purification step.

The terms “polypeptide”, “peptide” and “protein” are used interchangeably herein and refer to polymeric forms of amino acids of any length, which may include genetically encoded and non-genetically encoded amino acids, chemically or biochemically modified or derivatized amino acids, and polypeptides having modified peptide backbones. The term includes fusion proteins, including, but not limited to, fusion proteins having heterologous amino acid sequences, fusions having heterologous and homologous leader sequences (with or without N-terminal methionine residues); and the like.

The “percent amino acid sequence identity (%)” with respect to the reference polypeptide sequence is defined as the percentage of amino acid residues in the candidate sequence identical to the amino acid residues in the reference polypeptide sequence when a gap is introduced as necessary to achieve maximal percent sequence identity and no conservative substitutions are considered as part of sequence identity. The comparison for purposes of determining percent amino acid sequence identity can be achieved in a variety of ways within the skill in the art, for example using publicly available computer softwares, such as BLAST, BLAST-2, ALIGN or Megalign (DNASTAR) software. Those skilled in the art can determine appropriate parameters for aligning sequences, including any algorithm needed to achieve the maximum comparison over the full length of the sequences being compared. However, for purposes of the present invention, the percent amino acid sequence identity value is generated using the sequence comparison computer program ALIGN-2.

In the case of comparing amino acid sequences using ALIGN-2, the % amino acid sequence identity of a given amino acid sequence A relative to a given amino acid sequence B (or may be expressed as a given amino acid sequence A having or containing a certain % amino acid sequence identity relative to, with or for a given amino acid sequence B) is calculated as follows: fraction X/Y×100

wherein X is the number of identically matched amino acid residues scored by the sequence alignment program ALIGN-2 in the alignment of A and B using the program, and wherein Y is the total number of amino acid residues in B. It will be appreciated that where the length of amino acid sequence A is not equal to the length of amino acid sequence B, the % amino acid sequence identity of A relative to B will not be equal to the % amino acid sequence identity of B relative to A. Unless specifically stated otherwise, all the % amino acid sequence identity values used herein are obtained using the ALIGN-2 computer program as described in the previous paragraph.

As used herein, the terms “treatment” and “treating” refer to obtaining a desired pharmacological and/or physiologic effect. The effect may be complete or partial prevention of a disease or its symptoms and/or partial or complete cure of the disease and/or its symptoms, and includes: (a) prevention of the disease from developing in a subject that may have a predisposition to the disease but has not been diagnosed as having the disease; (b) suppression of the disease, i.e., blocking its formation; and (c) alleviation of the disease and/or its symptoms, i.e., eliminating the disease and/or its symptoms.

The terms “individual”, “subject” and “patient” are used interchangeably herein and refer to mammals, including, but not limited to, murine (rats and mice), non-human primates, humans, dogs, cats, hoofed animals (e.g., horses, cattle, sheep, pigs, goats) and so on.

“Therapeutically effective amount” or “effective amount” refers to an amount of plasminogen sufficient to achieve the prevention and/or treatment of a disease when administered to a mammal or another subject to treat the disease. The “therapeutically effective amount” will vary depending on the plasminogen used, the severity of the disease and/or its symptoms, as well as the age, body weight of the subject to be treated, and the like.

Preparation of the Plasminogen of the Present Invention

Plasminogen can be isolated and purified from nature for further therapeutic uses, and can also be synthesized by standard chemical peptide synthesis techniques. When chemically synthesized, a polypeptide can be subjected to liquid or solid phase synthesis. Solid phase polypeptide synthesis (SPPS) is a method suitable for chemical synthesis of plasminogen, in which the C-terminal amino acid of a sequence is attached to an insoluble support, followed by the sequential addition of the remaining amino acids in the sequence. Various forms of SPPS, such as Fmoc and Boc, can be used to synthesize plasminogen. Techniques for solid phase synthesis are described in Barany and Solid-Phase Peptide Synthesis; pp. 3-284 in The Peptides: Analysis, Synthesis, Biology. Vol. 2: Special Methods in Peptide Synthesis, Part A., Merrifield, et al. J. Am. Chem. Soc., 85: 2149-2156 (1963); Stewart et al. Solid Phase Peptide Synthesis, 2nd ed. Pierce Chem. Co., Rockford, Ill. (1984); and Ganesan A. 2006 Mini Rev. Med Chem. 6:3-10 and Camarero J A et al. 2005 Protein Pept Lett. 12:723-8. Briefly, small insoluble porous beads are treated with a functional unit on which a peptide chain is constructed. After repeated cycles of coupling/deprotection, the attached solid phase free N-terminal amine is coupled to a single N-protected amino acid unit. This unit is then deprotected to expose a new N-terminal amine that can be attached to another amino acid. The peptide remains immobilized on the solid phase before it is cut off.

Standard recombinant methods can be used to produce the plasminogen of the present invention. For example, a nucleic acid encoding plasminogen is inserted into an expression vector, so that it is operably linked to a regulatory sequence in the expression vector. Expression regulatory sequence includes, but is not limited to, promoters (e.g., naturally associated or heterologous promoters), signal sequences, enhancer elements and transcription termination sequences. Expression regulation can be a eukaryotic promoter system in a vector that is capable of transforming or transfecting eukaryotic host cells (e.g., COS or CHO cells). Once the vector is incorporated into a suitable host, the host is maintained under conditions suitable for high-level expression of the nucleotide sequence and collection and purification of plasminogen.

A suitable expression vector is usually replicated in a host organism as an episome or as an integral part of the host chromosomal DNA. In general, an expression vector contains a selective marker (e.g., ampicillin resistance, hygromycin resistance, tetracycline resistance, kanamycin resistance or neomycin resistance) to facilitate detection of those exogenous cells transformed with a desired DNA sequence.

Escherichia coli is an example of prokaryotic host cells that can be used to clone a polynucleotide encoding the subject antibody. Other microbial hosts suitable for use include Bacillus, for example, Bacillus subtilis and other species of enterobacteriaceae (such as Salmonella spp. and Serratia spp.), and various Pseudomonas spp. In these prokaryotic hosts, expression vectors can also be generated which will typically contain an expression control sequence (e.g., origin of replication) that is compatible with the host cell. In addition, there will be many well-known promoters, such as the lactose promoter system, the tryptophan (trp) promoter system, the beta-lactamase promoter system or the promoter system from phage lambda. Optionally in the case of manipulation of a gene sequence, a promoter will usually control expression, and has a ribosome binding site sequence and the like to initiate and complete transcription and translation.

Other microorganisms, such as yeast, can also be used for expression. Saccharomyces (e.g., S. cerevisiae) and Pichia are examples of suitable yeast host cells, in which a suitable vector has an expression control sequence (e.g., promoter), an origin of replication, a termination sequence and the like, as required. A typical promoter comprises 3-phosphoglycerate kinase and other glycolytic enzymes. Inducible yeast promoters specifically include promoters derived from alcohol dehydrogenase, isocytochrome C, and enzymes responsible for maltose and galactose utilization.

In addition to microorganisms, mammalian cells (e.g., mammalian cells cultured in cell culture in vitro) can also be used to express and generate the anti-Tau antibody of the present invention (e.g., a polynucleotide encoding a subject anti-Tau antibody). See Winnacker, From Genes to Clones, VCH Publishers, N.Y., N.Y. (1987). Suitable mammalian host cells include CHO cell lines, various Cos cell lines, HeLa cells, myeloma cell lines and transformed B cells or hybridomas. Expression vectors for these cells may comprise an expression control sequence, such as an origin of replication, promoter and enhancer (Queen et al. Immunol. Rev. 89:49 (1986)), as well as necessary processing information sites, such as a ribosome binding site, RNA splice site, polyadenylation site and transcription terminator sequence. Examples of suitable expression control sequences are promoters derived from white immunoglobulin gene, SV40, adenovirus, bovine papilloma virus, cytomegalovirus and the like. See Co et al. J. Immunol. 148:1149 (1992).

Once synthesized (chemically or recombinantly), the plasminogen of the present invention can be purified according to standard procedures in the art, including ammonium sulfate precipitation, affinity column, column chromatography, high performance liquid chromatography (HPLC), gel electrophoresis and the like. The plasminogen is substantially pure, e.g., at least about 80% to 85% pure, at least about 85% to 90% pure, at least about 90% to 95% pure, or 98% to 99% pure or purer, for example free of contaminants such as cell debris, macromolecules other than the subject antibody and the like.

Pharmaceutical Formulations

A therapeutic formulation can be prepared by mixing plasminogen of a desired purity with an optional pharmaceutical carrier, excipient or stabilizer (Remington's Pharmaceutical Sciences, 16th edition, Osol, A. ed. (1980)) to form a lyophilized preparation or an aqueous solution. Acceptable carriers, excipients and stabilizers are non-toxic to the recipient at the dosages and concentrations employed, and include buffers, such as phosphates, citrates and other organic acids; antioxidants, including ascorbic acid and methionine; preservatives (e.g., octadecyl dimethyl benzyl ammonium chloride; hexane chloride diamine; benzalkonium chloride and benzethonium chloride; phenol, butanol or benzyl alcohol; alkyl p-hydroxybenzoates, such as methyl or propyl p-hydroxybenzoate; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight polypeptides (less than about 10 residues); proteins, such as serum albumin, gelatin or immunoglobulins; hydrophilic polymers, such as polyvinylpyrrolidone; amino acids, such as glycine, glutamine, asparagine, histidine, arginine or lysine; monosaccharides, disaccharides and other carbohydrates, including glucose, mannose or dextrins; chelating agents, such as EDTA; sugars, such as sucrose, mannitol, fucose or sorbitol; salt-forming counterions, such as sodium; metal complexes (e.g., zinc-protein complexes); and/or non-ionic surfactants, such as TWEEN™, PLURONICS™ or polyethylene glycol (PEG). Preferred lyophilized anti-VEGF antibody formulations are described in WO 97/04801, which is incorporated herein by reference.

The formulations of the invention may also comprise one or more active compounds required for the particular condition to be treated, preferably those that are complementary in activity and have no side effects with one another, for example anti-hypertensive drugs, anti-arrhythmic drugs, drugs for treating diabetes mellitus, and the like.

The plasminogen of the present invention may be encapsulated in microcapsules prepared by techniques such as coacervation or interfacial polymerization, for example, it may be incorporated in a colloid drug delivery system (e.g., liposomes, albumin microspheres, microemulsions, nanoparticles and nanocapsules), or incorporated in hydroxymethylcellulose or gel-microcapsules and poly-(methyl methacrylate) microcapsules in macroemulsions. These techniques are disclosed in Remington's Pharmaceutical Sciences, 16th edition, Osol, A. Ed. (1980).

The plasminogen of the present invention for in vivo administration must be sterile. This can be easily achieved by filtration through a sterile filtration membrane before or after freeze drying and reconstitution.

The plasminogen of the present invention can be prepared into a sustained-release preparation. Suitable examples of sustained-release preparations include solid hydrophobic polymer semi-permeable matrices having a shape and containing glycoproteins, such as films or microcapsules. Examples of sustained-release matrices include polyesters, hydrogels (e.g., poly(2-hydroxyethyl-methacrylate)) (Langer et al. J. Biomed. Mater. Res., 15: 167-277 (1981); and Langer, Chem. Tech., 12:98-105 (1982)), or poly(vinyl alcohol), polylactides (U.S. Pat. No. 3,773,919, and EP 58,481), copolymer of L-glutamic acid and □ ethyl-L-glutamic acid (Sidman et al. Biopolymers 22:547(1983)), nondegradable ethylene-vinyl acetate (Langer et al. supra), or degradable lactic acid-glycolic acid copolymers such as Lupron Depot™ (injectable microspheres composed of lactic acid-glycolic acid copolymer and leuprolide acetate), and poly D-(−)-3-hydroxybutyric acid. Polymers, such as ethylene-vinyl acetate and lactic acid-glycolic acid, are able to persistently release molecules for 100 days or longer, while some hydrogels release proteins for a shorter period of time. A rational strategy for protein stabilization can be designed based on relevant mechanisms. For example, if the aggregation mechanism is discovered to be formation of an intermolecular S—S bond through thio-disulfide interchange, stability is achieved by modifying sulfhydryl residues, lyophilizing from acidic solutions, controlling moisture content, using appropriate additives, and developing specific polymer matrix compositions.

Administration and Dosage

The pharmaceutical composition of the present invention is administered in different ways, for example by intravenous, intraperitoneal, subcutaneous, intracranial, intrathecal, intraarterial (e.g., via carotid), and intramuscular administration.

Preparations for parenteral administration include sterile aqueous or non-aqueous solutions, suspensions and emulsions. Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate. Aqueous carriers include water, and alcoholic/aqueous solutions, emulsions or suspensions, including saline and buffered media. Parenteral vehicles include sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, or fixed oils. Intravenous vehicles include liquid and nutrient supplements, electrolyte supplements and the like. Preservatives and other additives may also be present, for example, such as antimicrobial agents, antioxidants, chelating agents and inert gases.

The medical staff will determine the dosage regimen based on various clinical factors. As is well known in the medical field, the dosage of any patient depends on a variety of factors, including the patient's size, body surface area, age, the specific compound to be administered, sex, frequency and route of administration, overall health and other drugs administered simultaneously. The dosage range of the pharmaceutical composition comprising plasminogen of the present invention may be, for example, such as about 0.0001 to 2000 mg/kg, or about 0.001 to 500 mg/kg (such as 0.02 mg/kg, 0.25 mg/kg, 0.5 mg/kg, 0.75 mg/kg, 10 mg/kg and 50 mg/kg) of the subject's body weight daily. For example, the dosage may be 1 mg/kg body weight or 50 mg/kg body weight, or in the range of 1 mg/kg-50 mg/kg, or at least 1 mg/kg. Dosages above or below this exemplary range are also contemplated, especially considering the above factors. The intermediate dosages in the above range are also included in the scope of the present invention. A subject may be administered with such dosages daily, every other day, weekly or based on any other schedule determined by empirical analysis. An exemplary dosage schedule includes 1-10 mg/kg for consecutive days. During administration of the drug of the present invention, the therapeutic effect and safety are required to be assessed real-timely.

Articles of Manufacture or Kits

One embodiment of the present invention relates to an article of manufacture or a kit comprising plasminogen of the present invention or plasmin useful in the treatment of angiocardiopathy and its related conditions caused by diabetes mellitus. The article preferably includes a container, label or package insert. Suitable containers include bottles, vials, syringes and the like. The container can be made of various materials, such as glass or plastic. The container contains a composition that is effective to treat the disease or condition of the present invention and has a sterile access (for example, the container may be an intravenous solution bag or vial containing a plug that can be pierced by a hypodermic injection needle). At least one active agent in the composition is plasminogen/plasmin. The label on or attached to the container indicates that the composition is used to treat the angiocardiopathy and its related conditions caused by diabetes mellitus according to the present invention. The article may further comprise a second container containing a pharmaceutically acceptable buffer, such as phosphate buffered saline, Ringer's solution and glucose solution. It may further comprise other substances required from a commercial and user perspective, including other buffers, diluents, filters, needles and syringes. In addition, the article comprises a package insert with instructions for use, including, for example, instructions to direct a user of the composition to administer to a patient the plasminogen composition and other drugs for treating an accompanying disease.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a representative image of Sirius red staining of lung after administration of plasminogen to bleomycin-induced systemic sclerosis model mice for 21 days. A represents the control group administered with vehicle PBS, B represents the group administered with plasminogen, and C represents the quantitative analysis results. The results showed that in the bleomycin-induced systemic sclerosis mouse model, the degree of pulmonary fibrosis (indicated by arrow) in mice in the group administered with vehicle PBS was higher than that in the group administered with plasminogen; while in the group administered with plasminogen, the morphology of pulmonary alveolar walls in mice was close to normal, cells with the inflammatory level was remarkably reduced, the degree of fibrosis was remarkably lower than that in the group administered with vehicle PBS, and the statistical difference was significant (* indicates P<0.05).

FIG. 2 shows a representative image of Sirius red staining of aortic sinus after administration of plasminogen to ApoE atherosclerosis model mice for 30 days. A and C refer to the control group administered with vehicle PBS, and B and D refer to the group administered with plasminogen. The results showed that the area of collagen deposition (indicated by arrow) in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS, indicating that plasminogen can reduce the level of aortic sinus fibrosis in arteriosclerosis model mice.

FIG. 3 shows a representative image of Sirius red staining of liver after administration of plasminogen to carbon tetrachloride-induced hepatic fibrosis model mice for 14 days. A represents a blank control group, B represents a control group administered with vehicle PBS, and C represents a group administered with plasminogen. The results showed that in the group administered with plasminogen, the collagen deposition was remarkably less than that in the control group administered with vehicle PBS, and the level of collagen deposition in mice was close to that in blank control mice. It indicates that plasminogen can reduce collagen deposition in liver, and ameliorate hepatic fibrosis in hepatic fibrosis model mice.

FIG. 4 shows a representative image of Sirius red staining of aortic sinus after administration of plasminogen to 16-week hyperlipemia model mice for 30 days. A and C refer to the control group administered with vehicle PBS, and B and D refer to the group administered with plasminogen. The results showed that the area of collagen deposition (indicated by arrow) on the intima of the aortic sinus wall in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS, indicating that plasminogen can reduce the level of intimal fibrosis of the aortic sinus wall in hyperlipemia model mice.

FIG. 5 shows a representative image of Sirius red staining of skin after administration of plasminogen to bleomycin-induced systemic sclerosis model mice for 21 days. A represents the blank control group, B represents the control group administered with vehicle PBS, C represents the group administered with plasminogen, and D represents the group with impaired PLG activity. The results showed that in the bleomycin-induced systemic sclerosis mouse model, the collagen fiber bundles in the upper dermis were remarkably increased, the collagen fibers were thick and big, and dense in arrangement, and the dermal layer was thickened in the group administered with vehicle PBS and the group with impaired PLG activity; while in the group administered with plasminogen, the fibroblasts in the dermal layer were remarkably less than those in the group administered with vehicle PBS, and the thickness of the dermal layer of the skin was close to the normal level.

FIG. 6 shows a representative image of Sirius red staining of heart after administration of plasminogen to bleomycin-induced systemic sclerosis model mice for 21 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. Studies have found that in the bleomycin-induced systemic sclerosis mouse model, the degree of collagen deposition (indicated by arrow) in heart in the control group administered with vehicle PBS was higher than that in the group administered with plasminogen. It indicates that plasminogen can effectively reduce bleomycin-induced cardiac fibrosis.

FIG. 7 shows a representative image of Sirius red staining of kidney after administration of plasminogen to bleomycin-induced systemic sclerosis model mice for 21 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. The results showed that in the bleomycin-induced systemic sclerosis mouse model, the degree of collagen fibrosis (indicated by arrow) in the kidney in the control group administered with vehicle PBS was higher than that in the group administered with plasminogen. It indicates that plasminogen can effectively reduce bleomycin-induced renal fibrosis.

FIG. 8 shows observed results of immunostaining of type IV collagen in the kidney after administration of plasminogen to 24- to 25-week-old diabetic mice for 31 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. The results showed that the positive staining (indicated by arrow) of IV collagen in the group administered with plasminogen was remarkably higher than that in the control group administered with vehicle PBS, indicating that plasminogen can ameliorate renal fibrosis in diabetic mice.

FIG. 9 shows observed results of masson staining of kidney after administration of plasminogen to 26-week-old diabetic mice for 35 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. The results showed that in the control group administered with vehicle PBS, glomerular mesangial hyperplasia existed, mesangial matrix increased, renal interstitial fibrosis was mild (indicated by arrow), and the hyperplastic fibrosis was blue. In the group administered with plasminogen, the glomerular mesangial cells and matrix were remarkably less than those in the control group, and renal interstitial fibrosis was remarkably reduced. It indicates that plasminogen can ameliorate fibrotic lesions in the kidneys of diabetic mice.

FIG. 10 shows observed results of masson staining of heart after administration of plasminogen to 24- to 25-week-old diabetic mice for 31 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. The results showed that in the control group administered with vehicle PBS, blue hyperplastic collagen fibers (indicated by arrow) could be seen between myocardial fibers, showing mild myocardial fibrosis; while in the group administered with plasminogen, a few light blue hyperplastic collagen fibers could be seen between myocardial fibers, and the myocardial fibrosis was remarkably alleviated compared with the control group. It indicates that plasminogen can ameliorate cardiac fibrosis in diabetic mice.

FIG. 11 shows a representative image of Sirius red staining of heart after administration of plasminogen to 17- to 18-week-old diabetic mice for 35 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. The results showed that the deposition of collagen fibers (indicated by arrow) in mice in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS. It indicates that plasminogen can reduce cardiac fibrosis in relatively young (17- to 18-week-old) diabetic mice.

FIG. 12 shows a representative image of Sirius red staining of heart after administration of plasminogen to 26- to 27-week-old diabetic mice for 35 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. The results showed that the collagen deposition (indicated by arrow) in mice in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS. It indicates that plasminogen can attenuate cardiac fibrosis in relatively old (26- to 27-week-old) diabetic mice.

FIG. 13 shows observed results of immunostaining of type IV collagen in the kidney after administration of plasminogen to cisplatin-induced renal fibrosis model mice for 7 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. The results showed that the positive expression (indicated by arrow) of type IV collagen in the kidney in the control group administered with vehicle PBS was remarkably higher than that in the group administered with plasminogen. It indicates that plasminogen can ameliorate renal fibrosis in cisplatin-induced renal fibrosis model mice.

FIG. 14 shows a representative image of Sirius red staining of heart after administration of plasminogen to ApoE atherosclerosis model mice for 30 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. The results showed that the collagen deposition (indicated by arrow) in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS, indicating that plasminogen can alleviate cardiac fibrosis in ApoE atherosclerosis model mice.

FIG. 15 shows a representative image of Sirius red staining of heart after administration of plasminogen to C57 hyperlipemia model mice for 30 days. A represents the control group administered with vehicle PBS, and B represents the group administered with plasminogen. The results showed that the collagen deposition (indicated by arrow) in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS, indicating that plasminogen can alleviate cardiac fibrosis in hyperlipemia model mice.

FIG. 16 shows observed results of Sirius red staining of kidney after administration of plasminogen to purine-induced chronic renal injury model mice for 10 days. A represents the control group administered with vehicle PBS, B represents the group administered with plasminogen, C represents the group with impaired PLG activity, and D represents the quantitative analysis results. The collagen deposition (indicated by arrow) in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS and the group with impaired PLG activity, and the quantitative analysis showed a significant statistical difference between the group administered with plasminogen and the group with impaired PLG activity (* indicates P<0.05). It indicates that plasminogen can alleviate renal fibrosis induced by chronic renal injury, and promote the repair of renal injury.

FIG. 17 shows the observed results of Sirius red-staining for pancreatic islets after administration of plasminogen to 24- to 25-week-old diabetic mice for 31 days. A represents the control group administered with vehicle PBS, B represents the group administered with plasminogen, and C represents the quantitative analysis results. The results showed that the collagen deposition (indicated by arrow) in the pancreatic islet of mice in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS, and the statistical difference was significant (* indicates P<0.05). It indicates that plasminogen can ameliorate injury and fibrosis of the pancreatic islet caused by diabetes mellitus.

FIG. 18 shows observed results of Sirius red staining of kidney after administration of plasminogen to 3% cholesterol hyperlipemia model mice for 30 days. A represents the blank control group, B represents the control group administered with vehicle PBS, C represents the group administered with plasminogen, and D represents the quantitative analysis results. The results showed that the collagen deposition in kidney (indicated by arrow) in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS, and the statistical difference was significant; and in the group administered with plasminogen, fibrosis was substantially restored to a normal level. It indicates that plasminogen can effectively reduce renal fibrosis in 3% cholesterol hyperlipemia model mice.

FIG. 19 shows observed results of Sirius red staining of liver after administration of plasminogen to carbon tetrachloride-induced hepatic fibrosis model mice for 28 days. A represents the blank control group, B represents the control group administered with vehicle PBS, C represents the group administered with plasminogen, and D represents the quantitative analysis results. The results showed that the collagen deposition (indicated by arrow) in the group administered with plasminogen was remarkably less than that in the control group administered with vehicle PBS, and the statistical difference was significant (* indicates P<0.05); compared with the control group administered with vehicle PBS, the level of collagen deposition in mice in the group administered with plasminogen was closer to that in blank control mice. It indicates that plasminogen can reduce collagen deposition in liver, and ameliorate hepatic fibrosis in hepatic fibrosis model mice.

EXAMPLES Example 1. Plasminogen Lowers Pulmonary Fibrosis in Systemic Sclerosis Mice

Seventeen 12-week-old male C57 mice were randomly divided into two groups, 11 mice in the control group administered with vehicle PBS, and 6 mice in the group administered with plasminogen. The mice were weighed and grouped on the day when the experiment began, i.e., Day 0. Model establishment and administration began from Day 1, wherein mice in both groups were injected with bleomycin subcutaneously at a dose of 0.1 mg/0.1 mL/mouse/day to induce systemic sclerosis^([26]), and plasminogen or PBS was administered for 21 consecutive days for model establishment. Mice in the group administered with plasminogen were injected with plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS in the same manner. The mice were sacrificed on Day 22. The lung tissues were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed lung tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 200×.

Studies have found that in the bleomycin-induced systemic sclerosis mouse model, it was observed under a microscope that the degree of collagen fibrosis (indicated by arrow) in the group administered with vehicle PBS (FIG. 1A) was higher than that in the group administered with plasminogen (FIG. 1B); while in the group administered with plasminogen, the morphology of pulmonary alveolar walls in mice was close to the normal level, the inflammatory cells were remarkably reduced, the degree of fibrosis was remarkably lower than that in the group administered with vehicle PBS, and the statistical difference was significant (FIG. 1C). It indicates that plasminogen can effectively reduce lung tissue fibrosis in bleomycin-induced systemic sclerosis mice.

Example 2. Plasminogen Ameliorates Aortic Sinus Fibrosis in ApoE Atherosclerosis Mice

Thirteen 6-week-old male ApoE mice were fed with a high-fat and high-cholesterol diet (Nantong TROPHIC, TP2031) for 16 weeks to induce the atherosclerosis model^([31,32]). 50 μL of blood was taken from each model mouse three days before administration, and the total cholesterol (T-CHO) content was detected. The mice were randomly divided into two groups based on the T-CHO content, 7 mice in the control group administered with vehicle PBS, and 6 mice in the group administered with plasminogen. The first day of administration was set as Day 1. Mice in the group administered with plasminogen were injected with human plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS via the tail vein. The mice were administered for 30 days and sacrificed on Day 31. The hearts were fixed in 4% paraformaldehyde for 24 to 48 hours, then sedimented in 15% and 30% sucrose at 4° C. overnight, respectively, and embedded in OCT. The frozen sections were 8 μm thick. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 40× (FIGS. 2A and 2B) and 200× (FIGS. 2C and 2D).

The results showed that the area of collagen deposition (indicated by arrow) on the intima of the aortic sinus wall in the group administered with plasminogen (FIGS. 2B and D) was remarkably less than that in the control group administered with vehicle PBS (FIGS. 2A and C), indicating that plasminogen can reduce the level of aortic sinus fibrosis in arteriosclerosis model mice.

Example 3. Plasminogen Ameliorates Carbon Tetrachloride-Induced Hepatic Fibrosis

Fifteen 9-week-old female C57 mice were randomly divided into three groups, a blank control group, a control group administered with vehicle PBS, and a group administered with plasminogen, 5 mice in each group. Mice in the control group administered with vehicle PBS and the group administered with plasminogen were injected with carbon tetrachloride intraperitoneally at a dose of 1 mL/kg body weight, three times a week for two consecutive weeks, to establish the hepatic fibrosis model^([36,37]); while the blank control mice were injected with a corresponding volume of corn oil according to the injection method of model mice.

Carbon tetrachloride required to be diluted with corn oil, and the dilution ratio of carbon tetrachloride to corn oil was 1:3. Administration began after model establishment. The first day of administration was recorded as Day 1. Mice in the group administered with plasminogen were injected with human plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and mice in the control group administered with vehicle PBS were injected with an equal volume of PBS via the tail vein, both lasting for 14 consecutive days. The blank control group was not treated with injection. The mice were sacrificed on Day 15. The livers were fixed in 4% paraformaldehyde for 24 hours. The fixed livers were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red for 60 min, the sections were flushed with running water. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol and returned to blue with ammonia water, flushed with running water, dried and sealed. The sections were observed under an optical microscope at 200×.

The results showed that the collagen deposition in the group administered with plasminogen (FIG. 3C) was remarkably less than that in the control group administered with vehicle PBS (FIG. 3B), and compared to the group administered with PBS, the level of collagen deposition in mice in the group administered with plasminogen was closer to that in blank control mice (FIG. 3A). It indicates that plasminogen can reduce collagen deposition in liver, and ameliorate hepatic fibrosis in hepatic fibrosis model mice.

Example 4. Plasminogen Reduces Aortic Sinus Fibrosis in 16-Week Hyperlipemia Model Mice

Eleven 6-week-old male C57 mice were fed with a high-fat and high-cholesterol diet (Nantong TROPHIC, TP2031) for 16 weeks to induce the hyperlipemia model^([30,31]). This model was designated as the 16-week hyperlipemia model. The model mice continued to be fed with a high-cholesterol diet. 50 μL of blood was taken from each mouse three days before administration, and the total cholesterol (T-CHO) content was detected. The mice were randomly divided into two groups based on the T-CHO content, 6 mice in the control group administered with vehicle PBS, and 5 mice in the group administered with plasminogen. The first day of administration was recorded as Day 1. Mice in the group administered with plasminogen were injected with human plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS via the tail vein. The mice were administered for 30 days and sacrificed on Day 31. The heart materials were taken and fixed in 4% paraformaldehyde for 24 to 48 hours. The fixed tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The aortic sinus sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 40× (FIGS. 4A and 4B) and 200× (FIGS. 4C and 4D).

The results showed that the area of collagen deposition (indicated by arrow) on the intima of the aortic sinus wall in the group administered with plasminogen (FIGS. 4B and 4D) was remarkably less than that in the control group administered with vehicle PBS (FIGS. 4A and 4C), indicating that plasminogen can alleviate the level of aortic sinus fibrosis in hyperlipemia model mice.

Example 5. Plasminogen Lowers Skin Fibrosis in Systemic Sclerosis Mice

Fifteen 12-week-old male C57 mice were randomly divided into three groups, a blank control group, a control group administered with vehicle PBS (PBS refers to Phosphate Buffer Saline, as a vehicle of plasminogen herein), and a group administered with plasminogen, 5 mice in each group, and five 13-week-old mice with impaired PLG activity were taken. The mice were weighed and grouped on the day when the experiment began, i.e., Day 0. Model establishment and administration began from the next day, wherein mice in the control group administered with vehicle PBS and the group administered with plasminogen as well as mice with impaired PLG activity were injected with bleomycin subcutaneously at a dose of 0.1 mg/0.1 mL/mouse/day to induce systemic sclerosis^([26)]. Mice in the blank control group were injected with normal saline subcutaneously at a dose of 0.1 mL/mouse/day; meanwhile, on Day 1, plasminogen or PBS was administered for 21 consecutive days for model establishment. Mice in the group administered with plasminogen were injected with plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, an equal volume of PBS was administered to mice in the control group administered with vehicle PBS, and the normal mouse group and mice with impaired PLG activity were not treated. The mice were sacrificed on Day 22. The back skin tissues were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed skin tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 100×.

Sirius red staining allows for long-lasting staining of collagen. As a special staining method for pathological sections, Sirius red staining can show the collagen tissue specifically.

The results showed that in the bleomycin-induced systemic sclerosis mouse model, it was observed under a microscope that the collagen fiber bundles in the upper dermis were remarkably increased, the collagen fibers were thick and big, and dense in arrangement, and the dermal layer was thickened in mice in the group administered with vehicle PBS (FIG. 5B) and the group with impaired PLG activity (FIG. 5D); while in the group administered with plasminogen (FIG. 5C), the fibroblasts in the dermal layer were remarkably less than those in the control group administered with vehicle PBS, and the thickness of the dermal layer of the skin was substantially close to the normal level (FIG. 5A). It indicates that plasminogen can effectively reduce bleomycin-induced skin fibrosis.

Example 6. Plasminogen Lowers Cardiac Fibrosis in Systemic Sclerosis Mice

Ten 12-week-old male C57 mice were randomly divided into two groups, 5 mice in each of the control group administered with vehicle PBS and the group administered with plasminogen. The mice were weighed and grouped on the day when the experiment began, i.e., Day 0. Model establishment and administration began from Day 1, wherein mice were injected with bleomycin subcutaneously at a dose of 0.1 mg/0.1 mL/mouse/day to induce systemic sclerosis^([26]), and plasminogen or PBS was administered for 21 consecutive days. Mice in the group administered with plasminogen were injected with plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS via the tail vein. The mice were sacrificed on Day 22. The hearts were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed hearts were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 200×.

Studies have found that in the bleomycin-induced systemic sclerosis mouse model, it was observed under a microscope that the collagen deposition in heart in the control group administered with vehicle PBS (FIG. 6A) was higher than that in the group administered with plasminogen (FIG. 6B). It indicates that plasminogen can effectively reduce bleomycin-induced cardiac fibrosis.

Example 7. Plasminogen Lowers Renal Fibrosis in Systemic Sclerosis Mice

Ten 12-week-old male C57 mice were randomly divided into two groups, 5 mice in each of the control group administered with vehicle PBS and the group administered with plasminogen. The mice were weighed and grouped on the day when the experiment began, i.e., Day 0. Model establishment and administration began from Day 1, wherein all mice were injected with bleomycin subcutaneously at a dose of 0.1 mg/0.1 mL/mouse/day to induce systemic sclerosis, and plasminogen or PBS was administered for 21 consecutive days for model establishment. Mice in the group administered with plasminogen were injected with plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and mice in the control group administered with vehicle PBS were injected with an equal volume of PBS via the tail vein. The mice were sacrificed on Day 22. The kidneys were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed kidneys were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 200×.

The results showed that in the bleomycin-induced systemic sclerosis mouse model, the degree of collagen fibrosis (indicated by arrow) in the kidney in the control group administered with vehicle PBS (FIG. 7A) was higher than that in the group administered with plasminogen (FIG. 7B). It indicates that plasminogen can effectively reduce bleomycin-induced renal fibrosis.

Example 8. Plasminogen Lowers Collagen Deposition in Kidney of Diabetic Mice

Ten 24- to 25-week-old male db/db mice were randomly divided into two groups, five mice in each of a control group administered with vehicle PBS and a group administered with plasminogen. The mice were weighed and grouped on the day when the experiment began, i.e. Day 0. Plasminogen or PBS was administered from day 1 for 31 consecutive days. Mice in the group administered with plasminogen were injected with plasminogen at a dose of 2 mg/0.2 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS. The mice were sacrificed after administration of plasminogen for 31 days. The kidney tissues were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed kidney tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The thickness of the tissue sections was 4 μm. The sections were dewaxed and rehydrated and washed with water once. The sections were incubated with 3% hydrogen peroxide for 15 minutes and washed with 0.01M PBS twice for 5 minutes each time. The sections were blocked with 10% normal goat serum (Vector laboratories, Inc., USA) for 1 hour, and after the time was up, the serum was thrown away, and the tissues were circled with a PAP pen. The sections were incubated with rabbit anti-mouse polyclonal antibody (Abcam) against IV collagen overnight at 4° C. and washed with TBS twice for 5 minutes each time. The sections were incubated with a secondary antibody, goat anti-rabbit IgG (HRP) antibody (Abcam), for 1 hour at room temperature and washed with TBS twice. The sections were developed with a DAB kit (Vector laboratories, Inc., USA). After washed with water three times, the sections were counterstained with hematoxylin for 30 seconds and flushed with running water for 5 minutes. After dehydration with alcohol gradient, permeabilization with xylene, and sealing with a neutral gum, the sections were observed under an optical microscope at 200×.

Diabetic nephropathy is a chronic complication of diabetes mellitus, and glomerular sclerosis and renal interstitial fibrosis are typical pathological changes^([27]).

The results showed that the positive staining of IV collagen in the group administered with plasminogen (FIG. 8B) was remarkably more than that in the control group administered with vehicle PBS (FIG. 8A), indicating that plasminogen can reduce collagen deposition (indicated by arrow) in the kidney tissue, and suggesting that plasminogen is expected to prevent renal tissue fibrosis caused by diabetes mellitus by reducing collagen deposition in the kidney tissue.

Example 9. Plasminogen Ameliorates Renal Fibrosis in Diabetic Mice

Ten 26-week-old male db/db mice were randomly divided into two groups, 5 mice in each of the control group administered with vehicle PBS and the group administered with plasminogen. The mice were weighed and grouped on the day when the experiment began, i.e. Day 0. Plasminogen or PBS was administered from day 1 for 35 consecutive days. Mice in the group administered with plasminogen were injected with plasminogen at a dose of 2 mg/0.2 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS. The mice were sacrificed on Day 36. The kidney tissues were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed kidney tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The thickness of the tissue sections was 4 μm. The sections were dewaxed and rehydrated and then put into a potassium dichromate solution overnight. The sections were stained with iron hematocylin for 3 to 5 minutes, and flushed slightly with running water. The sections were differentiated with 1% hydrochloric acid in alcohol, treated with ammonia water for 1 second, and rinsed with water. The sections were stained in ponceau acid fuchsin fluid for 8 minutes, and rinsed rapidly in water. The sections were treated with 1% phosphomolybdic acid aqueous solution for about 2 minutes, and counterstained with aniline blue solution for 6 minutes. The sections were rinsed with 1% glacial acetic acid for about 1 minute. The sections were sealed after dehydration with absolute ethanol, and permeabilization with xylene, and were observed under an optical microscope at 200×.

Masson staining can reveal tissue fibrosis. The results showed that in the control group administered with vehicle PBS (FIG. 9A), glomerular mesangial hyperplasia existed, mesangial matrix increased, renal interstitial fibrosis was mild (indicated by arrow), and the hyperplastic fibrosis was blue. In the group administered with plasminogen (FIG. 9B), the glomerular mesangial cells and matrix were remarkably less than those in the control group, and renal interstitial fibrosis was remarkably reduced. It indicates that plasminogen can ameliorate renal fibrosis in diabetic mice.

Example 10. Plasminogen Ameliorates Cardiac Fibrosis in 24- to 25-Week-Old Diabetic Mice

Ten 24- to 25-week-old male db/db mice were randomly divided into two groups, five mice in each of a control group administered with vehicle PBS and a group administered with plasminogen. The mice were weighed and grouped on the day when the experiment began, i.e. Day 0. Plasminogen or PBS was administered from day 1 for 31 consecutive days. Mice in the group administered with plasminogen were injected with plasminogen at a dose of 2 mg/0.2 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS. The mice were sacrificed after administration of plasminogen for 31 days. The heart tissues were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed heart tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The thickness of the tissue sections was 4 μm. The sections were dewaxed and rehydrated and then put into a potassium dichromate solution overnight. The sections were stained with iron hematocylin for 3 to 5 minutes, and flushed slightly with running water. The sections were differentiated with 1% hydrochloric acid in alcohol, treated with ammonia water for 1 second, and rinsed with water. The sections were stained in ponceau acid fuchsin fluid for 8 minutes, and rinsed rapidly in water. The sections were treated with 1% phosphomolybdic acid aqueous solution for about 2 minutes, and counterstained with aniline blue solution for 6 minutes. The sections were rinsed with 1% glacial acetic acid for about 1 minute. The sections were sealed after dehydration with absolute ethanol, and permeabilization with xylene, and were observed under an optical microscope at 200×.

The most common complication of diabetes mellitus is excessive accumulation of connective tissues (pathological fibrosis). Myocardial interstitial fibrosis may be the characteristic pathological change of diabetic cardiomyopathy^([28-29]).

Masson staining can reveal tissue fibrosis. The results showed that in the control group administered with vehicle PBS (FIG. 10A), blue hyperplastic collagen fibers (indicated by arrow) could be seen between myocardial fibers, showing mild myocardial fibrosis; while in the group administered with plasminogen (FIG. 10B), a few light blue hyperplastic collagen fibers could be seen between myocardial fibers, and the myocardial fibrosis was remarkably alleviated compared with the control group. It indicates that plasminogen can ameliorate cardiac fibrosis in diabetic mice.

Example 11. Plasminogen Lowers Collagen Deposition in Heart of 17- to 18-Week-Old Diabetic Mice

Eight 17- to 18-week-old male db/db mice were randomly divided into two groups, four mice in each of the control group administered with vehicle PBS and the group administered with plasminogen. The mice were weighed and grouped on the day when the experiment began, i.e. Day 0. Plasminogen or PBS was administered from day 1 for 35 consecutive days. Mice in the group administered with plasminogen were injected with plasminogen at a dose of 2 mg/0.2 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS. The mice were sacrificed after administration of plasminogen for 35 days. The heart tissues were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed hearts were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 200×.

The results showed that the deposition of collagen fibers (indicated by arrow) in mice in the group administered with plasminogen (FIG. 11B) was remarkably less than that in the control group administered with vehicle PBS (FIG. 11A). It indicates that plasminogen can reduce collagen deposition in the heart tissue, and suggests that plasminogen is expected to reduce heart tissue fibrosis in relatively young (17- to 18-week-old) diabetic mice by lowering collagen deposition in the heart tissue.

Example 12. Plasminogen Lowers Collagen Deposition in Heart of 26- to 27-Week-Old Diabetic Mice

Nine 26- to 27-week-old male db/db mice were randomly divided into two groups, 5 mice in the control group administered with vehicle PBS, and 4 mice in the group administered with plasminogen. The mice were weighed and grouped on the day when the experiment began, i.e. Day 0. Plasminogen or PBS was administered from day 1 for 35 consecutive days. Mice in the group administered with plasminogen were injected with plasminogen at a dose of 2 mg/0.2 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS. The mice were sacrificed after administration of plasminogen for 35 days. The heart tissues were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed hearts were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red for 60 min, the sections were flushed with running water. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol and returned to blue with ammonia water, flushed with running water, dried and sealed. The sections were observed under an optical microscope at 200×.

The results showed that the deposition of collagen fibers (indicated by arrow) in mice in the group administered with plasminogen (FIG. 12B) was remarkably less than that in the control group administered with vehicle PBS (FIG. 12A). It indicates that plasminogen can reduce collagen deposition in the heart tissue, and suggests that plasminogen is expected to reduce heart tissue fibrosis in relatively old (26- to 27-week-old) diabetic mice by lowering collagen deposition in the heart tissue.

Example 13. Plasminogen Lowers Renal Fibrosis in Cisplatin-Induced Renal Fibrosis Model Mice

Ten healthy 8-9-week-old male C57 mice were randomly divided into two groups, five mice in each of the control group administered with vehicle PBS and the group administered with plasminogen. After the completion of grouping, single intraperitoneal injection of cisplatin was performed at 10 mg/Kg body weight to establish the renal fibrosis model^([30]). After the model was established, mice in the group administered with plasminogen were administered with plasminogen at a dose of 1 mg/0.1 mL/mouse/day via tail vein injection, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS. The mice were weighed and grouped on the day when the experiment began, i.e. day 0; the mice received intraperitoneal injection of cisplatin for modelling on day 1, and were administered with plasminogen or vehicle PBS 3 hours after the modelling, for an administration period of 7 days. The mice were sacrificed on Day 8. The kidneys were fixed in 4% paraformaldehyde fixative for 24 hours. The fixed kidney tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The thickness of the tissue sections was 5 μm. The sections were dewaxed and rehydrated and washed with water once. The sections were repaired with citric acid for 30 minutes, and gently rinsed with water after cooling at room temperature for 10 minutes. The sections were incubated with 3% hydrogen peroxide for 15 minutes, and the tissues were circled with a PAP pen. The sections were blocked with 10% goat serum (Vector laboratories, Inc., USA) for 1 hour, and after the time was up, the goat serum liquid was discarded. The sections were incubated with rabbit anti-mouse IV collagen antibody (Abcam) overnight at 4° C. and washed with TBS twice for 5 minutes each time. The sections were incubated with a secondary antibody, goat anti-rabbit IgG (HRP) antibody (Abcam), for 1 hour at room temperature and washed with TBS twice for 5 minutes each time. The sections were developed with a DAB kit (Vector laboratories, Inc., USA). After washing with water three times, the sections were counterstained with hematoxylin for 30 seconds, returned to blue with running water for 5 minutes, and washed with TBS once. After dehydration with a gradient, permeabilization and sealing, the sections were observed under an optical microscope at 200×.

Cisplatin is a broad-spectrum anti-tumor drug with extensive clinical application and reliable efficacy. However, it has severe nephrotoxicity, mainly results in renal tubular and renal interstitial injuries which eventually develop into renal fibrosis^([30]). The experimental results showed that the positive expression (indicated by arrow) of type IV collagen in the kidney in the control group administered with vehicle PBS (FIG. 13A) was remarkably higher than that in the group administered with plasminogen (FIG. 13B). It indicates that plasminogen can ameliorate renal fibrosis in cisplatin-induced renal fibrosis model mice.

Example 14. Plasminogen Ameliorates the Level of Cardiac Fibrosis in ApoE Atherosclerosis Mice

Thirteen 6-week-old male ApoE mice were fed with a high-fat and high-cholesterol diet (Nantong TROPHIC, TP2031) for 16 weeks to induce the atherosclerosis^([31,32]). 50 μL of blood was taken from each mouse three days before administration, and the total cholesterol concentration was detected. The mice were randomly divided into two groups based on the detection results, 7 mice in the control group administered with vehicle PBS, and 6 mice in the group administered with plasminogen. The first day of administration was set as Day 1. Mice in the group administered with plasminogen were injected with human plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS via the tail vein. The administration lasted for 30 days, during which mice continued to be fed with a high-fat and high-cholesterol diet. The mice were sacrificed on Day 31. The hearts were fixed in 4% paraformaldehyde for 24 to 48 hours. The fixed tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 200×.

The results showed that the collagen deposition (indicated by arrow) in the group administered with plasminogen (FIG. 14B) was remarkably less than that in the control group administered with vehicle PBS (FIG. 14A), suggesting that plasminogen can prevent and lower cardiac fibrosis induced by atherosclerosis by reducing collagen deposition in the heart tissue of ApoE atherosclerosis model mice.

Example 15. Plasminogen Lowers Cardiac Fibrosis in Hyperlipemia Model Mice

Eleven 6-week-old male C57 mice were fed with a high-fat and high-cholesterol diet (Nantong TROPHIC, TP2031) for 16 weeks to induce hyperlipemia^([33,34]). 50 μL of blood was taken from each mouse three days before administration, and the total cholesterol concentration was detected. The mice were randomly divided into two groups based on the detection results, 6 mice in the control group administered with vehicle PBS, and 5 mice in the group administered with plasminogen. The first day of administration was recorded as Day 1. Mice in the group administered with plasminogen were injected with human plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS via the tail vein. The administration lasted for 30 days, during which mice continued to be fed with a high-fat and high-cholesterol diet. The mice were sacrificed on Day 31. The heart tissues were fixed in 4% paraformaldehyde for 24 to 48 hours. The fixed tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 200×.

The results showed that the collagen deposition (indicated by arrow) in the group administered with plasminogen (FIG. 15B) was remarkably less than that in the control group administered with vehicle PBS (FIG. 15A), suggesting that plasminogen can prevent and lower cardiac fibrosis induced by hyperlipemia by reducing collagen deposition in the heart tissue of hyperlipemia model mice.

Example 16. Plasminogen Repairs Renal Fibrosis in Chronic Renal Failure Model

Twelve 8- to 9-week-old male mice with normal PLG activity and six male mice with impaired PLG activity were taken. The mice with normal PLG activity were randomly divided into two groups, 6 mice in each of the group administered with plasminogen and the control group administered with vehicle PBS. Three groups of mice were fed with a 0.25% purine diet (Nantong TROPHIC) every day to establish the chronic renal failure model^([35]). The day of model establishment was recorded as Day 1, and administration began at the same time. Mice in the group administered with plasminogen were administered with plasminogen at a dose of 1 mg/0.1 mL/mouse/day, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS in the same manner, both lasting for 10 consecutive days for model establishment. The mice with impaired PLG activity were not treated. The mice were sacrificed on Day 11. The kidneys were fixed in 4% paraformaldehyde for 24 hours. The fixed kidneys were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red for 60 min, the sections were flushed with running water. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol and returned to blue with ammonia water, flushed with running water, dried and sealed. The sections were observed under an optical microscope at 200×.

The results showed that the collagen deposition (indicated by arrow) in the group administered with plasminogen (FIG. 16B) was remarkably less than that in the control group administered with vehicle PBS (FIG. 16A) and the group with impaired PLG activity (FIG. 16C), and the statistical difference between the group administered with plasminogen and the group with impaired PLG activity was significant (P=0.018) (FIG. 16D). It indicates that plasminogen can significantly alleviate collagen deposition in kidney tissues of animals with chronic renal injury, thus preventing and alleviating renal fibrosis induced by chronic renal injury.

Example 17. Plasminogen Reduces Collagen Deposition in the Pancreatic Islet of Diabetic Mice

Sixteen 24- to 25-week-old male db/db mice were randomly divided into two groups, 10 mice in the group administered with plasminogen, and 6 mice in the control group administered with vehicle PBS. Mice in the group administered with plasminogen were injected with human plasminogen at a dose of 2 mg/0.2 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS via the tail vein. The mice were weighed and grouped on the day when the experiment began, i.e. Day 0. Plasminogen or PBS was administered from day 1 for 31 consecutive days. On day 32, the mice were sacrificed, and the pancreas was taken and fixed in 4% paraformaldehyde. The fixed pancreas tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red for 60 min, the sections were flushed with running water. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol and returned to blue with ammonia water, flushed with running water, dried and sealed. The sections were observed under an optical microscope at 200×.

The results showed that the collagen deposition (indicated by arrow) in the pancreatic islet of the mice in the group administered with plasminogen (FIG. 17B) was remarkably lower than that in the control group administered with vehicle PBS (FIG. 17A), and the statistical difference was significant (FIG. 17C). It indicates that plasminogen can significantly alleviate collagen deposition in pancreatic tissues of diabetic mice, thus preventing and alleviating pancreatic injury and fibrosis.

Example 18. Plasminogen Lowers Renal Fibrosis in 3% Cholesterol Hyperlipemia Model Mice

Sixteen 9-week-old male C57 mice were fed with a 3% cholesterol high-fat diet (Nantong TROPHIC) for 4 weeks to induce hyperlipemia^([30·31]) This model was designated as the 3% cholesterol hyperlipemia model. The model mice continued to be fed with the 3% cholesterol high-fat diet. Another five male C57 mice of the same week age were taken as the blank control group, and were fed with a normal maintenance diet during the experiment. 50 μL of blood was taken from each mouse three days before administration, and the total cholesterol was detected. The model mice were randomly divided into two groups based on the total cholesterol concentration and the body weight, i.e., the group administered with plasminogen, and the control group administered with vehicle PBS, 8 mice in each group. The first day of administration was recorded as Day 1. Mice in the group administered with plasminogen were injected with human plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS via the tail vein. The mice were administered for 30 days. After the mice were administered on day 30, the mice were sacrificed on Day 31. The kidney materials were taken and fixed in 4% paraformaldehyde for 24 to 48 hours. The fixed tissues were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red in saturated picric acid for 30 min, the sections were flushed with running water for 2 min. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol, returned to blue with ammonia water, flushed with running water, dried and sealed with a neutral gum. The sections were observed under an optical microscope at 200×.

The results showed that the collagen deposition in kidney (indicated by arrow) in the group administered with plasminogen (FIG. 18C) was remarkably less than that in the control group administered with vehicle PBS (FIG. 18B), and the statistical difference was significant (FIG. 18D); while in the group administered with plasminogen, fibrosis was substantially restored to a normal level (FIG. 18A). It indicates that plasminogen can effectively reduce renal fibrosis in 3% cholesterol hyperlipemia model mice.

Example 19. Plasminogen Reduces Collagen Deposition in Liver During Induction of Hepatic Fibrosis by Carbon Tetrachloride

Twenty 7- to 8-week-old female C57 mice were randomly divided into three groups, 5 mice in the blank control group, 7 mice the control group administered with vehicle PBS, and 8 mice in the group administered with plasminogen. Mice in the control group administered with vehicle PBS and the group administered with plasminogen were injected with carbon tetrachloride intraperitoneally at a dose of 1 mL/kg body weight, three times a week for four consecutive weeks, to establish the hepatic fibrosis model^([36,37]); while the blank control mice were injected with a corresponding volume of corn oil intraperitoneally. Carbon tetrachloride required to be diluted with corn oil, and the dilution ratio of carbon tetrachloride to corn oil was 1:3. Administration began on the day of model establishment, i.e., Day 1. Mice in the group administered with plasminogen were injected with human plasminogen at a dose of 1 mg/0.1 mL/mouse/day via the tail vein, and an equal volume of PBS was administered to mice in the control group administered with vehicle PBS via the tail vein, both lasting for 28 days. The blank control group was not treated with injection. The mice were sacrificed on Day 29. The livers were fixed in 4% paraformaldehyde for 24 hours. The fixed livers were paraffin-embedded after dehydration with alcohol gradient and permeabilization with xylene. The tissue sections was 3 μm thick. The sections were dewaxed and rehydrated and washed with water once. After stained with 0.1% Sirius red for 60 min, the sections were flushed with running water. After stained with hematoxylin for 1 min, the sections were flushed with running water, differentiated with 1% hydrochloric acid in alcohol and returned to blue with ammonia water, flushed with running water, dried and sealed. The sections were observed under an optical microscope at 200×.

The results showed that the collagen deposition in the group administered with plasminogen (FIG. 19C) was remarkably less than that in the control group administered with vehicle PBS (FIG. 19B), and the statistical difference was significant (FIG. 19D); compared with the control group administered with vehicle PBS, the level of collagen deposition (indicated by arrow) in mice in the group administered with plasminogen was closer to that in blank control mice (FIG. 19A). It indicates that plasminogen can reduce collagen deposition in liver, and ameliorate hepatic fibrosis in hepatic fibrosis model mice.

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The invention claimed is:
 1. A method for ameliorating pulmonary collagen deposition or fibrosis caused by a pulmonary tissue injury in a subject having pulmonary collagen deposition or fibrosis, wherein the subject is not plasminogen-deficient, comprising administering an effective amount of plasminogen having at least 98% sequence identity to the full-length sequence of SEQ ID NOs. 2, 4, 8, 10, or 12 to the subject, wherein the pulmonary tissue injury comprises an ischemic reperfusion injury, an immune injury, a chemical-induced injury, or an inflammatory injury.
 2. The method of claim 1, wherein the pulmonary tissue injury comprises an immune injury.
 3. The method of claim 2, wherein the immune injury comprises an autoimmune response-induced injury.
 4. The method of claim 1, comprising ameliorating a pulmonary fibrosis-related condition in the subject, wherein the pulmonary fibrosis-related condition comprises a condition resulting from decreased pulmonary function, pulmonary dysfunction, or loss of pulmonary function.
 5. The method of claim 4, wherein the pulmonary fibrosis-related condition comprises pulmonary arterial hypertension, pulmonary heart disease, dyspnea, or pulmonary encephalopathy.
 6. The method of claim 1, wherein the plasminogen is administered in combination with one or more other drugs or therapeutic means.
 7. The method of claim 6, wherein the one or more other drugs comprise: a hypolipidemic drug, an anti-platelet drug, an antihypertensive drug, a vasodilator, a hypoglycemic drug, an anticoagulant drug, a thrombolytic drug, a hepatoprotective drug, an anti-fibrosis drug, an anti-arrhythmia drug, a cardiotonic drug, a diuretic drug, an anti-tumor drug, a radiotherapeutic or chemotherapeutic drug, an inflammatory regulatory drug, an immunomodulatory drug, an antiviral drug, or an antibiotic.
 8. The method of claim 1, wherein the plasminogen has at least 99% sequence identity with the full-length sequence of SEQ ID NO. 2, and still has the plasminogen activity.
 9. The method of claim 1, wherein the plasminogen is a protein that comprises a plasminogen active fragment and still has the plasminogen activity.
 10. The method of claim 1, wherein the plasminogen is selected from Glu-plasminogen, mini-plasminogen, micro-plasminogen, or delta-plasminogen.
 11. The method of claim 1, wherein the plasminogen is a natural or synthetic human plasminogen.
 12. The method of claim 1, wherein the plasminogen is administered to the subject at a dosage of 1-100 mg/kg, 1-50 mg/kg, or 1-10 mg/kg, daily, every other day, or weekly.
 13. The method of claim 12, wherein the administration is repeated at least once.
 14. The method of claim 12, wherein the plasminogen is administered at least daily.
 15. The method of claim 1, wherein the pulmonary tissue injury comprises an ischemic reperfusion injury.
 16. The method of claim 1, wherein the pulmonary tissue injury comprises a chemical-induced injury.
 17. A method for ameliorating pulmonary collagen deposition or fibrosis in a subject having pulmonary collagen deposition or fibrosis, wherein the subject is not plasminogen-deficient, comprising administering an effective amount of plasminogen having at least 98% sequence identity to the full-length sequence of SEQ ID NOs. 2, 4, 8, 10, or 12 to the subject, wherein the subject is susceptible to pulmonary fibrosis, has a tendency of pulmonary fibrosis, or suffers from other diseases accompanied by pulmonary fibrosis, wherein the pulmonary collagen deposition or fibrosis is caused by inhalation of toxic chemicals in the lung tissue of the subject, or caused or accompanied by a pulmonary lesion in the subject.
 18. The method of claim 17, wherein the pulmonary collagen deposition or fibrosis is caused by inhalation of toxic chemicals.
 19. The method of claim 18, wherein the pulmonary collagen deposition or fibrosis is a pulmonary collagen deposition or fibrosis accompanied by chronic obstructive pulmonary disease.
 20. The method of claim 17, wherein the pulmonary lesion is pneumonia, lung cancer, pulmonary embolism, pulmonary tuberculosis, pulmonary heart disease, or pulmonary injury.
 21. The method of claim 17, wherein the pulmonary lesion is pneumonia.
 22. The method of claim 17, wherein the pulmonary lesion is pulmonary injury.
 23. A method for ameliorating pulmonary fibrosis in a subject with idiopathic pulmonary fibrosis, wherein the subject is not plasminogen-deficient, comprising administering an effective amount of plasminogen having at least 98% sequence identity to the full-length sequence of SEQ ID NOs. 2, 4, 8, 10, or 12 to the subject. 